1. Field:
The present disclosure relates generally to nondestructive inspection (NDI) standards and, in particular, to nondestructive inspection standards for porosity. Still more particularly, the present disclosure relates to a method and apparatus for creating nondestructive inspection standards for porosity using computed tomography (CT).
2. Background:
Nondestructive inspection (NDI) refers to the group of analysis techniques that are used to evaluate the properties of an object without altering the object. Nondestructive inspection may also be referred to as nondestructive examination (NDE), nondestructive testing (NDT), or nondestructive evaluation (NDE). Different types of nondestructive inspection techniques may be used to evaluate composite materials and objects comprised of composite materials. These different techniques include, but are not limited to, ultrasonic testing (UT), radiographic testing, and vibration analysis.
Oftentimes, standards are created for use in evaluating an object using nondestructive inspection. As used herein, a “standard” is a reference article or sample of material having a set of properties that are the same as the object being evaluated. These properties may include, for example, without limitation, material composition, geometry, thickness, and/or other types of properties.
In some cases, standards are used to calibrate the nondestructive inspection system used to test an object. Additionally, standards may be inspected using the nondestructive inspection system that is used to test the object. Data generated by the nondestructive inspection system for these standards may be used as reference data for comparison with part data generated by the nondestructive inspection system for the part. In other words, the reference data may be used for comparison when evaluating the part data.
As one illustrative example, a group of standards may be established for evaluating the porosity of a part comprised of composite material. In this example, each standard in the group of standards is a sample of composite material that has been previously identified as having a particular porosity.
However, with some currently available methods for establishing nondestructive inspection standards, the time, effort, and/or cost required to form samples of composite material and identify the porosity for each of these samples may be greater than desired. For example, with some currently available methods, forming a sample may require performing any number of sanding operations, polishing operations, cutting operations, and/or other types of operations to prepare at least one edge of the sample for testing. These operations may be more time-consuming than desired.
Further, the sample may then be analyzed using, for example, without limitation, ultrasound testing techniques. Software may then be used to estimate a level of porosity for an edge of the sample based on a height and weight of the sample. This estimated porosity may then be used to estimate a level of porosity for the entire sample. However, this type of estimation may be less accurate than desired.
Consequently, the standards established using these types of currently available methods may not allow the object for which the standards were established to be evaluated as well as desired. Therefore, it would be desirable to have a method and apparatus that takes into account at least some of the issues discussed above, as well as other possible issues.